首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   81158篇
  免费   1908篇
  国内免费   153篇
化学   45445篇
晶体学   909篇
力学   2364篇
综合类   3篇
数学   12254篇
物理学   22244篇
  2022年   568篇
  2021年   788篇
  2020年   976篇
  2019年   918篇
  2018年   1457篇
  2017年   1294篇
  2016年   2345篇
  2015年   1767篇
  2014年   2026篇
  2013年   4569篇
  2012年   4304篇
  2011年   4471篇
  2010年   3086篇
  2009年   2801篇
  2008年   3844篇
  2007年   3606篇
  2006年   3236篇
  2005年   3118篇
  2004年   2794篇
  2003年   2357篇
  2002年   2103篇
  2001年   2238篇
  2000年   1881篇
  1999年   1427篇
  1998年   1095篇
  1997年   995篇
  1996年   1062篇
  1995年   861篇
  1994年   898篇
  1993年   822篇
  1992年   917篇
  1991年   838篇
  1990年   880篇
  1989年   764篇
  1988年   790篇
  1987年   731篇
  1986年   678篇
  1985年   857篇
  1984年   857篇
  1983年   657篇
  1982年   693篇
  1981年   689篇
  1980年   580篇
  1979年   658篇
  1978年   628篇
  1977年   627篇
  1976年   646篇
  1975年   563篇
  1974年   554篇
  1973年   587篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Kinetics and Catalysis - A new ruthenium(II) cage complex with polar terminal groups in the apical substituents has been synthesized; the molecular design of the complex contributes to the...  相似文献   
3.
Fan  K.  Lu  R. S.  Liang  K. K.  Hou  Z. C. 《High Energy Chemistry》2022,56(4):264-269
High Energy Chemistry - Modification of Polyvinylidene fluoride (PVDF) by radiation grafting is a research hotspot in recent years. In this study, the monomer 2-Hydroxyethyl methacrylate (HEMA) was...  相似文献   
4.
Reactivity studies of the GeII→B complex L(Cl)Ge⋅BH3 ( 1 ; L=2-Et2NCH2-4,6-tBu2-C6H2) were performed to determine the effect on the GeII→B donation. N-coordinated compounds L(OtBu)Ge⋅BH3 ( 2 ) and [LGe⋅BH3]2 ( 3 ) were prepared. The possible tuning of the GeII→B interaction was proved experimentally, yielding compounds 1-PPh2-8-(LGe)-C10H6 ( 4 ) and L(Cl)Ge⋅GaCl3 ( 5 ) without a GeII→B interaction. In 5 , an unprecedented GeII→Ga coordination was revealed. The experimental results were complemented by a theoretical study focusing on the bonding in 1 − 5 . The different strength of the GeII→E (E=B, Ga) donation was evaluated by using energy decomposition analysis. The basicity of different L(X)Ge groups through proton affinity is also assessed.  相似文献   
5.
Journal of Analytical Chemistry - The present development involved a flow injection strategy using a mini-column of multiwalled carbon nanotubes and fluorescent detection (λex of 283 nm,...  相似文献   
6.
Meccanica - In this work we study, from the numerical point of view, a one-dimensional thermoelastic problem where the thermal law is of type III. Quasi-static microvoids are also assumed within...  相似文献   
7.
Set-Valued and Variational Analysis - In a Hilbert framework ℌ, we study the convergence properties of a Newton-like inertial dynamical system governed by a general maximally monotone...  相似文献   
8.
9.
Siberian Mathematical Journal - A lattice homomorphism between quasi-Banach lattices is known to be compact if and only if it is a sum of a series of rank one lattice...  相似文献   
10.
Riociguat is novel antihypertensive drug for treatment of pulmonary hypertension. As such, it is still being tested in many clinical and pharmacokinetic trials. Existing methods that determine serum riociguat and desmethylriociguat (DMR) are based solely on liquid chromatography with mass spectrometry. Therefore, we present a novel capillary electrophoresis with mass spectrometry method (CE-MS) for their determination in human serum as alternative method for ongoing trials. Complete resolution of both analytes was achieved by means of pH optimization of ammonium formate background electrolytes that are fully compatible with ESI/MS detection. Simple liquid-liquid extraction was used as sample pretreatment. The calibration dependence of the method was linear (in the range of 10–1000 ng/mL), with adequate accuracy (90.1–114.9%) and precision (13.4%). LOD and LOQ were arbitrarily set at 10 ng/mL for both analytes. Clinical applicability was validated using serum samples from patients treated with riociguat in pharmacokinetic study and the results corresponded with reference HPLC-MS/MS values. Capillary electrophoresis proved to be sensitive and selective tool for the analysis of riociguat and DMR.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号